Due to local government restrictions, instead of building individual towers for each individual operator's use, different wireless network operators typically co-locate their equipment at a single network tower. This has resulted in the rise of so-called “tower companies” that own wireless network towers and lease space on the towers to different wireless network operators. This arrangement requires a wireless network operator to negotiate a lease agreement if it is desired to add antennas or cable runs between existing antennas and a backhaul network.
In some cases a wireless network operator is willing to pay for additional antennas, but due to regulatory wind-loading limits, a tower company cannot allow additional antennas on a particular tower.